Several people listed as part of the “Veterans for Trump coalition” formed by Donald Trump following his incendiary comments about John McCain’s war record have denied they are part of the group, the Guardian has learned.

Trump’s campaign announced the formation of the New Hampshire-based group in response to criticism of the business mogul’s labelling of McCain, who spent five and a half years in a North Vietnamese jail, where he was tortured, as “ not a war hero ”.

A number of people were named as members of “Veterans for Trump” on Trump’s election website . “These veterans have pledged their support to Mr Trump in the primary, and they will be advocating for him,” a press release said.

But when the Guardian contacted several claimed Veterans for Trump members on Friday, three said they had never heard of the organisation and had not signed up as members.

“I don’t know anything about it,” said Ernie Fusi, an 88-year-old second world war veteran from Atkinson, New Hampshire. His name was among 51 “Veterans for Trump” whose details were sent out to the media and listed on Trump’s website.

“I haven’t told anyone I want to get in on that,” Fusi said. “I’m not going to do any campaigning.”

On Saturday, the Trump campaign disputed the accounts of those interviewed by the Guardian.

In an email, a spokeswoman said: “The campaign has written confirmation of support from each of the individuals listed as part of the New Hampshire Veterans Coalition, including those quoted in this story. We are extremely proud to have their support.”

Fusi said he was a Republican voter, although he had not gone to any meetings or speeches in this election cycle. He said he would not vote in the primary but would vote for whichever GOP candidate ran in the presidential election. He was unhappy about being named as a coalition member.

“I don’t like it,” he said. “’Cause I haven’t given anyone permission to send my name around.”

Donald Richards, a veteran based in Laconia, New Hampshire, was also named on the list of Veterans for Trump members along with his wife, Connie Richards. He said neither had signed up for the group.

“I’m not a member of the campaign, no,” he said. “I have no connection any more than anybody else does to him.”

The Trump campaign announced the formation of Veterans for Trump after the 69-year-old business mogul was roundly criticised for mocking McCain’s military history.

“He’s not a war hero. He’s a war hero because he was captured? I like people who weren’t captured,” Trump said in a campaign appearance in Iowa last Saturday.

The Veterans for Trump coalition was announced six days later. The revelation that several “members” of the Veterans for Trump coalition had never heard of the organisation, let alone knowingly joined it, raises questions as to the legitimacy of the coalition.